We know that Petra's equation is parallel to y = 2x - 4. Therefore, 2x will stay the same, otherwise the 2 lines won't be parallel. The only thing that changes is the y-intercept, the -4.
Change the -4 to c so that we can figure out what the y-intercept is of the line that passes through (-2,3).
Substitute in the co ordinates and solve for c.
Finally, rewrite the equation, with 7 in place of c.